Gaseous electric discharge device



, Feb. 5, 1935.

G. GAIDIES GASEOUS I ELECTRIC DISCHARGE DEVICE Filed Sept. 27. 1932 INVENTOR ATTORNEY Patentedfeb. 5, 1935 7 oasaous nmc'rmo DISCHARGE avies Georg Gaidi'es, Berlin-Pankow, Germany,- assignor to General Electric Company, acorporationot New York Application September In Ge 27, 1932, Serial 1510. 635,037

. nnany November 11,19 1

2 Claims.

The present invention relates to' gaseous electric discharge devices generally and more particularly the invention relates to such devices of the positive. column type in which metal vapor constitutes the gaseous atmosphereor is a component of the gaseous atmosphere.

The object of the invention is to provide. a high intensity light source being a gaseous electric discharge device useful in television, spectrometry, beacon work, or the like. Still further objects and advantages attaching to the device and to its use and operation will be apparent to those skilled in the art from the following particular description and from the appended claims. I

In accordance,with this object the device comprises an elongated container having a gaseous atmosphere therein and an anode and a cathode sealed therein. Said cathode is an elongated hollowchamber having a reentrant tube part' forming a. contracted opening in the direction of the anode'and the longitudinal aids of said tube part is coincident with the longitudinal axis of the container of the device. Said anode is an annular disk and the opening therein is concentric with the open tube part of said cathode. The positive column discharge between said anode and said cathode thus extends along, and is visible. end-on through the opening in said anode, in the direction of the longitudinal axis of the container. The length or depth of said hole low cathode is greater than twice the distance between said cathode and the anode- A vapor- "iZable metal is located in the interior of said cathode. By virtue of the particular shape of the cathode, and the arrangement of the anode and cathode the greater part 01' the length of the positive column discharge is located in the contracted opening in said cathode and the heat resulting from said discharge and from the glow discharge in said cathode plus the heat resulting from the cathode drop raises said cathode to a comparatively high temperature, but not to an incandescent temperature however, which causes a heavy vaporization of the vaporizable metal in said cathode which vapor conducts'the electric discharge in the device; Having the above structure and operating in the above manner the gaseus electric. discharge device is a spot light source of high intrinsic brilliancy.

In the drawing accompanying and .forming partof this specification an embodiment of the invention is view.

Referring to the drawing shown-in a sectional side elevational the device comprises 4 thereof having a reentrant tube 5 forming a contracted opening. The longitudinal axisof said tube 5 is coincident with the longitudinal axis of said container 1. Said electrode 2 .is the cathode and'is mounted on and supported by current inlead 3 sealed into said container 1. Electrode 6 is an annular disk, the diameter of the opening therein is approximately the sameas the diameter of the opening in said tube 5 and the center of said opening lies in the longitudinal axis of said tube 5. Said electrode 6 is the anode and is supported by current inlead '7 sealed into said container 1-.

A vaporizable metal, such as sodium; caesium or cadmium, is located in the interior of said electrode 2. The length or depth of said elec-- but not to .an incandescent temperature, which causes a strong vaporization of the vaporlzable metal in said electrode 2 which vapor-actively participates in conducting the electric discharge device.

Take, for. example, an electric discharge device having a gaseous filling comprising a mixture of neon and helium at a pressure of 3 mm. in which the distance between the anode 6 and the cathode 2 is 10 mm. and in which the cathode 2 is 60 mm. in length and mm. in diameter. With a current or 50 milliamperes the cathode 2 is heated to a temperature of aproximately 200 to 300 C. The vap'oriz'able metal, such as sodium, in said cathode 2 is vaporized at this temperature and "the spectrum of the emitted light is. strong in the transmitting or other special glass where desired. The smaller the diameter of the opening in the reentrant tube 5 the more concentrated I is the positive column discharge therein,- which increases the brilliancy or the light source, and said tube 5 guides the electric discharge along the longitudinalaxis of the container and prevents sputtered, unvaporized' metal particles from escaping from the interior of said electrode 2 and depositing on the wallsot said container 1.

The development of undesired deposits of condensed metal vapor on the walls or said container 1 1 is prevented by maintaining the walls of said container at a temperature higher than the condensation temperature of said metal vapor by the use of a double walled container, the space between said walls being evacuated or filled with a heat absorbing gas, such as argon, or a heat ab- Letters Patent of the United States is:---

1. An electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, at least one 01' said electrodesbeing a hollow cathode having an elongated re-entrant tube part close to the other electrode and containing a vaporizable material, said tube part being a contracted opening for said cathode, another of said electrodes being an annular disc anode the center of the opening therein lying in the longitudinal axis of said tube part, the length of said cathode being greater than twice the distance between said anode and said cathode, the greater path between said electrodes being in said cathode.

2. An electric discharge device comprising a container, electrodes sealed therein, a gaseous atmosphere therein, at least one or said electrodes being a hollow cathode having an- 'elon- Eatedreentrant tube part and containing sodium, :'said tube part being a contracted opening. for

said cathode, another of said electrodes'being an annular disc anode the center of the opening therein lying in the longitudinal axis oi said tube part, the length of said cathode being greater than twice the distance between said anode and said cathode, the greater part of the discharge path between said electrodes being in said cathode. I

' GEORG GAIDIES.

part of the discharge 

